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make width, height, area, rotation and centroid lazy

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since the rectangle constructor is a hot path any calculations slow the library down considerably. for this reason we move calculations for the following properties into the property getter:
* width (cached)
* height (cached)
* rotation
* area
* centroid

where values are cached they set their backing field once calculated. this won't be thread safe if the same rectangle is accessed on multiple threads.
This commit is contained in:
Eliot Jones
2020-01-28 15:33:08 +00:00
parent 0e84fa34a8
commit b585fe9581
1 changed files with 90 additions and 34 deletions
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124
src/UglyToad.PdfPig.Core/PdfRectangle.cs
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@@ -35,27 +35,75 @@
/// <summary>
/// Centroid point of the rectangle.
/// </summary>
public PdfPoint Centroid { get; }
public PdfPoint Centroid
{
get
{
var t = GetT();
var cosT = Math.Cos(t);
var sinT = Math.Sin(t);
var cx = Math.Min(BottomRight.X, Math.Min(TopLeft.X, Math.Min(BottomLeft.X, TopRight.X)))
+ (Width * cosT + Height * sinT) / 2.0;
var cy = Math.Min(BottomRight.Y, Math.Min(TopLeft.Y, Math.Min(BottomLeft.Y, TopRight.Y)))
+ (Height * cosT + Width * sinT) / 2.0;
return new PdfPoint(cx, cy);
}
}
private double width;
/// <summary>
/// Width of the rectangle.
/// </summary>
public double Width { get; }
public double Width
{
get
{
if (width == double.MinValue)
{
GetWidthHeight();
}
return width;
}
}
private double height;
/// <summary>
/// Height of the rectangle.
/// </summary>
public double Height { get; }
public double Height
{
get
{
if (height == double.MinValue)
{
GetWidthHeight();
}
return height;
}
}
/// <summary>
/// Rotation angle of the rectangle. Counterclockwise, in degrees.
/// </summary>
public double Rotation { get; }
public double Rotation
{
get
{
var rotation = GetT() * 180 / Math.PI;
return rotation;
}
}
/// <summary>
/// Area of the rectangle.
/// </summary>
public double Area { get; }
public double Area => Math.Abs(Width * Height);
/// <summary>
/// Left. This value is only valid if the rectangle is not rotated, check <see cref="Rotation"/>.
@@ -75,7 +123,7 @@
/// <summary>
/// Bottom. This value is only valid if the rectangle is not rotated, check <see cref="Rotation"/>.
/// </summary>
public double Bottom => BottomRight.Y < TopRight.Y ? BottomRight.Y : TopRight.Y;
public double Bottom => BottomRight.Y < TopRight.Y ? BottomRight.Y : TopRight.Y;
/// <summary>
/// Create a new <see cref="PdfRectangle"/>.
@@ -94,7 +142,8 @@
/// <param name="x2">Top right point's x coordinate of the rectangle.</param>
/// <param name="y2">Top right point's y coordinate of the rectangle.</param>
public PdfRectangle(short x1, short y1, short x2, short y2) :
this((double)x1, y1, x2, y2) { }
this((double)x1, y1, x2, y2)
{ }
/// <summary>
/// Create a new <see cref="PdfRectangle"/>.
@@ -118,32 +167,8 @@
BottomLeft = bottomLeft;
BottomRight = bottomRight;
double bx = Math.Max(Math.Abs(BottomRight.X - TopLeft.X), Math.Abs(BottomLeft.X - TopRight.X));
double by = Math.Max(Math.Abs(TopRight.Y - BottomLeft.Y), Math.Abs(TopLeft.Y - BottomRight.Y));
double t;
if (!BottomRight.Equals(BottomLeft))
{
t = Math.Atan2(BottomRight.Y - BottomLeft.Y, BottomRight.X - BottomLeft.X);
}
else
{
// handle the case where both bottom points are identical
t = Math.Atan2(TopLeft.Y - BottomLeft.Y, TopLeft.X - BottomLeft.X) - 1.5707963267949; // PI / 2
}
double cosT = Math.Cos(t);
double sinT = Math.Sin(t);
double cosSqSinSqInv = 1.0 / (cosT * cosT - sinT * sinT);
Rotation = t * 180 / Math.PI;
Width = cosSqSinSqInv * (bx * cosT - by * sinT);
Height = cosSqSinSqInv * (-bx * sinT + by * cosT);
Area = Width * Height;
double Cx = Math.Min(BottomRight.X, Math.Min(TopLeft.X, Math.Min(BottomLeft.X, TopRight.X))) + (Width * cosT + Height * sinT) / 2.0;
double Cy = Math.Min(BottomRight.Y, Math.Min(TopLeft.Y, Math.Min(BottomLeft.Y, TopRight.Y))) + (Height * cosT + Width * sinT) / 2.0;
Centroid = new PdfPoint(Cx, Cy);
width = double.MinValue;
height = double.MinValue;
}
/// <summary>
@@ -154,10 +179,41 @@
/// <returns>A new rectangle shifted on the y axis by the given delta value.</returns>
public PdfRectangle Translate(double dx, double dy)
{
return new PdfRectangle(TopLeft.Translate(dx, dy), TopRight.Translate(dx, dy),
return new PdfRectangle(TopLeft.Translate(dx, dy), TopRight.Translate(dx, dy),
BottomLeft.Translate(dx, dy), BottomRight.Translate(dx, dy));
}
private double GetT()
{
double t;
if (!BottomRight.Equals(BottomLeft))
{
t = Math.Atan2(BottomRight.Y - BottomLeft.Y, BottomRight.X - BottomLeft.X);
}
else
{
// handle the case where both bottom points are identical
t = Math.Atan2(TopLeft.Y - BottomLeft.Y, TopLeft.X - BottomLeft.X) - Math.PI / 2;
}
return t;
}
private void GetWidthHeight()
{
var bx = Math.Max(Math.Abs(BottomRight.X - TopLeft.X), Math.Abs(BottomLeft.X - TopRight.X));
var by = Math.Max(Math.Abs(TopRight.Y - BottomLeft.Y), Math.Abs(TopLeft.Y - BottomRight.Y));
var t = GetT();
var cosT = Math.Cos(t);
var sinT = Math.Sin(t);
var cosSqSinSqInv = 1.0 / (cosT * cosT - sinT * sinT);
width = cosSqSinSqInv * (bx * cosT - by * sinT);
height = cosSqSinSqInv * (-bx * sinT + by * cosT);
}
/// <inheritdoc />
public override string ToString()
{